JP2905624B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for an image forming apparatus such as a printer, and more particularly, to a structure of a skew feeding roller holder for supporting a skew feeding roller for positioning a sheet being conveyed in the left-right direction. About.

[0002]

2. Description of the Related Art There is known a sheet feeding device of an image forming apparatus such as a printer that positions a sheet being conveyed in a left-right direction by using an oblique roller.

[0003] As shown in FIG. 7, a side regulating member 65 for guiding one side edge S2 of a sheet S in a conveying path R of the sheet S and a conveying roller 61 for applying a conveying force to the sheet S are provided. And an oblique feed roller 62 pressed against the transport roller. The conveying roller 61 has a rotating shaft 61a perpendicular to the conveying direction of the sheet S, that is, the rotating shaft 61a perpendicular to the side regulating member 65. In contrast, the rotary shaft 62a slightly tilts toward the side regulating member 65. As a result, the sheet S passing through the nip portion N between the conveying roller 61 and the skew feeding roller 62 has a side regulating member 65
, A diagonal lateral force acts on the side edges S of the sheet S.
2 is pressed against the side regulating member 65 so that the position in the left-right direction is regulated.

[0004] The left-right positioning greatly affects the accuracy of image formation. If the position is inaccurate, image formation is not performed at a correct position on a sheet, that is, a so-called copy defect occurs.

[0005]

However, according to the prior art, the nip portion N between the conveying roller 61 and the skew feeding roller 62 has the outer peripheral surfaces of the cylindrical conveying roller 61 and the skew feeding roller 62, respectively. The abutting part,
Due to the fact that the respective rotating shafts 61a and 62a are not parallel, the contact area becomes extremely small.
The leading edge S1 of the sheet S supplied to the nip N is
There is a possibility that a portion that first comes into contact with the nip portion N may be damaged.

Further, since the outer peripheral surfaces of the conveying roller 61 and the oblique feed roller 62 are obliquely in contact with each other, there is a possibility that the leading edge S1 of the sheet S may not be properly guided to the nip portion N corresponding to the contact point. Was.

[0007] The damage to the leading edge S1 of the sheet S and the poor introduction of the sheet S to the nip portion N are factors that cause subsequent conveyance failure of the sheet S, particularly, skew feeding of the sheet S and paper jam. .

Therefore, the present invention provides a guide roller for guiding a leading edge of a sheet to a nip portion in a skew roller holder for supporting the skew roller, whereby a sheet is smoothly guided to a nip portion. It is an object of the present invention to provide a sheet feeding device in which a leading edge of a sheet is not damaged.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a configuration in which a conveying roller and a diagonal feeding roller that presses against the conveying roller are arranged in a sheet conveying path.
A sheet feeding device that positions a sheet right and left by pressing one side edge of the sheet against a side regulating member in the conveyance path by passing the sheet through a nip portion between the conveyance roller and the oblique feeding roller. , A skew roller holder having two ribs rotatably supporting the skew roller, and an urging member for urging the skew roller holder and pressing the roller against the conveying holder, the conveying roller An introduction guide is formed on the two ribs so as to protrude into the transport path immediately adjacent to the nip portion so as not to come into contact with the nip portion and to guide at least two portions of the leading edge of the sheet to the nip portion. I do.

[0010]

According to the above construction, the sheet supplied to the nip portion between the conveying roller and the oblique feed roller is guided and supplied to an introduction guide disposed immediately near the nip portion. Since the introduction guide protrudes into the sheet conveyance path and guides the sheet at at least two points on the leading edge of the sheet, even if the leading edge of the sheet abuts against the introduction guide, the force is applied to the sheet leading edge. Since the sheet is appropriately concentrated without being concentrated at one point of the edge, the force does not concentrate on only one point as in the case where the leading edge of the sheet directly contacts the nip portion, so that the sheet is not damaged.

In addition, by regulating the running path of the leading edge of the sheet by the introduction guide, the leading edge of the sheet can be supplied at a suitable angle with respect to the nip portion.

Further, since the introduction guide is formed in the inclined roller holder that rotatably supports the inclined roller, the relative positional relationship between the inclined roller forming the nip portion and the introduction guide is accurately maintained. The sheet can be smoothly guided to the nip portion.

This accuracy mainly depends on the component accuracy of the skew feeding roller and the skew feeding roller holder, and hardly depends on the assembling accuracy when the skew feeding roller holder is incorporated in the sheet conveying path.

[0014]

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a state in which the sheet feeding device of the present invention is incorporated in a printer. In FIG. 1, reference numeral 1 denotes a sheet S to be copied which is housed and which is detachably attached to the printer body. A paper feed tray, 2 is a swingable middle plate on which the sheets S are stacked, and 3 is an uppermost surface of the stacked sheets S.
A feeding roller 4 for feeding the sheet by applying a frictional force to the sheet, a separation claw 4 for preventing the sheet S from being double fed, and a biasing member 5 for urging the middle plate 2 upward to feed the sheet S to the rotating sheet feeding roller 3. , A manual feed port for manually feeding one sheet S, 7 a manual feed roller for conveying the manually fed sheet S, 8 a manual feed roller pressed against the manual feed roller 7, 9
Is a conveyance guide that guides the sheet S fed from the paper feed tray 1, 10 is a guide block that guides the sheet S fed from the paper feed tray 1 or the manual feed slot 6, and 11 is a feed block that is fed from the manual feed slot 6. A manual feed guide for guiding the sheet S, a transport roller 12 for transporting the sheet S fed from the paper feed tray 1, and a diagonal transport roller 13 opposed to the transport roller 12. An oblique feed roller having a rotating shaft 13a inclined in a direction of pressing the sheet S against a side regulating member (reference plate) 29, an oblique feed roller holder 14 that rotatably holds the oblique feed roller 13 of FIG. The roller holder 14 is pressurized, and the skew feeding roller 13
2, a skew feeding spring for applying a conveying force and a skew feeding force to the sheet S, 20 is a pair of transfer guides, 21 is a photosensitive drum, 22 is a laser scanner, 23 is a transfer roller, 24 is a transfer guide, and 25 is a fixing. Reference numeral 26 denotes an outer discharge guide, 27 denotes an inner discharge guide, and 28 denotes a discharge tray.

FIG. 2 is a detailed view of the vicinity of the oblique feed roller 13 in FIG. 1 and a sectional view of a part thereof.
Denotes a conveying roller, 13 denotes a skew roller, and 14 denotes a skew roller holder provided with two ribs 30 and 31 for rotatably holding the skew roller 13. Rotary shaft 12 of paper feed roller 12
a is arranged at a right angle to the reference plate 29,
The rotation shaft 13a is slightly inclined toward the reference plate 29 with respect to the rotation shaft 12a. Thereby, a nip portion N formed by the outer peripheral portion of the sheet feeding roller 12 and the inclined roller 13 is formed.
When the two rotation shafts 12a and 13a are parallel to each other, they are formed substantially in a point shape, whereas they are formed in a substantially linear shape.
The oblique feeding force toward the reference plate 29 is applied to the sheet S that is going to pass through the nip portion N. Also, two ribs 30, 3
In FIG. 1, an introduction guide G protruding into the transport path R immediately before the nip portion N is formed. The two introduction guides are arranged at the same position in the sheet S transport direction, that is, along the leading edge S1 of the sheet S, and the leading edge S1 of the sheet S
Are guided smoothly to the nip portion N by guiding the two portions smoothly. The sheet S guided to the nip portion N is temporarily received by the introduction guide G before coming into contact with the nip portion N.

According to the above configuration, the sheet S fed from the paper feed tray 1 is image-formed as follows.

First, the sheets S stacked on the middle plate 2 supported by the sheet feeding tray 1 are rotated by the rotation of the sheet feeding roller 3.
The uppermost sheet is pressed by the pressure spring 5 against the sheet feed roller 3 and starts moving by receiving a frictional force. At this time, the multiply fed sheets S are separated by the separation claws 4 and only one sheet is fed. The fed sheet S is transported by the transport guide 9.
The traveling direction is guided by the block guide 10 and the nip portion N between the conveying roller 12 and the oblique feeding roller 13. Immediately before the sheet S is introduced into the nip portion N, the leading edge S1 is guided by the introduction guide G formed on the ribs 30 and 31 of the oblique feed roller holder 14, and smoothly enters the nip portion N. Due to the force of the skew feeding spring 15, the sheet S receives the conveying force and the skew feeding force, and advances with one of its side edges S2 abutting on the reference plate 29.

Next, the ribs 3 of the oblique feed roller holder 14 disposed near the junction with the transport path R on the manual feed guide 11 side
The sheet S is guided by the leading edge S <b> 1 by the introduction guides 0 and 31 in the same manner as described above, and enters the nip portion N of the conveying roller 12 and the skew feeding roller 13. At this time, the sheet S is simultaneously subjected to a conveying force and an oblique feeding force by the two pairs of conveying rollers 12 and 12 and the oblique feeding rollers 13 and 13, and is transferred while the side edge S 2 is in contact with the reference plate 29. It is guided by the guide pair 20 and enters the nip between the photosensitive drum 21 and the transfer roller 23. On the photosensitive drum 21, a latent image written by a laser beam by a laser scanner 22 is developed by a process unit (not shown).
This image is transferred onto the sheet S by 3. The sheet S to which the image has been transferred is guided to the conveyance guide 24 and enters the fixing device 25, where the image is fixed on the sheet S. Thereafter, the sheet S is transferred to the outer discharge guide 26 and the inner discharge guide 27.
And the paper is discharged and stacked on a paper discharge tray 28.

On the other hand, only one sheet S manually fed from the manual feed slot 6 enters the nip between the manual feed roller 7 and the manual feed roller 8, and the friction force is generated by pressing the manual feed roller 8 of a spring (not shown) against the manual feed roller 7. Occurs, and the sheet S is conveyed. Thus, the block guide 10, the manual feed guide 11, and the ribs 30 and 31 of the oblique feed roller holder 14 are provided.
The sheet S is guided by the introduction guide G of FIG.
Is fed into the nip portion N of the conveying roller 12 and the skew feeding roller 13, receives the conveying force and the skew feeding force, and is conveyed toward the transfer guide pair 20 with the side edge abutting on the reference plate 29.

With the above configuration, the following effects can be obtained. 1. Prior to the leading edge S1 of the sheet S entering the nip portion N between the skew roller 13 and the transport roller 12, at least two portions of the leading edge S1 are received almost simultaneously by the introduction guide G, and Shock at the time of entry is reduced, and it is possible to prevent subsequent occurrence of jam and skewing of the sheet. 2. To form the introduction guide G on the ribs 30 and 31 of the skew roller holder 14 that holds the skew roller 13, the nip portion N
Accumulation of the tolerance of the relative position between the guide G and the guide G is minimized, and the shape of the guide G with respect to the oblique feeding roller 13 can be made suitable. 3. When the introduction guide G is separate from the skew roller holder 14 at the confluence of the sheet S transport path R like the skew roller 13 on the downstream side, the introduction guide G is skewed due to processing restrictions such as bending. Although it tends to be separated from the rollers 13, in the embodiment, since the introduction guide G and the oblique feeding roller B can be brought close to each other, the introduction of the sheet S into the nip portion N is ensured. 4. Since the two introduction guides G of the oblique feed roller holder 14 are arranged along the leading edge S1 of the sheet S, the sheet S
At the same time, it is possible to scoop straight up two portions of the leading edge S1 of the sheet S, and it is difficult for the skewing or jamming of the sheet S thereafter.

FIGS. 3 (a) and 3 (b) show a second embodiment of the present invention, in which a skew feeding roller holder 32 having a different shape from the skew feeding roller holder 14 of the first embodiment is used. Have. However, other members are the same as in the previous embodiment.

In the present embodiment, the oblique feed roller holder 32
An introduction guide G is formed on a connecting member connecting the left and right ribs 30 and 31 of FIG. That is, the introduction guide G is formed over the entire width between the ribs 30 and 31, and as a result, a plurality of the introduction guides G are formed as compared with the case where the introduction guide G of the previous embodiment abuts two places of the leading edge S1 of the sheet S. It comes into contact continuously at a location, that is, at an appropriate width. According to this, in addition to the effects obtained by the first embodiment, when the sheet S comes into contact with the introduction guide G, the leading edge S1 is less likely to bend, so that more reliable conveyance can be obtained.

FIGS. 4 and 5 show a third embodiment of the present invention, in which 33 is a manual feed slot, 34 is a sheet S conveyed from a sheet feed tray (not shown), and a manual feed slot. A conveyance guide serving as a guide for the sheet S conveyed from 33, a manual feed roller 35 for conveying the manually inserted sheet S, a manual oblique feed roller 36 for conveying the sheet S while pressing the sheet S against the reference plate 29, and a manual feed roller 37 for manual feeding A manual upper guide 38 for guiding the sheet S and holding the manual skew feeding roller 36 in a vertically movable manner is bent into a U-shape, the end of which presses the manual skew feeding roller 36, and the other end of which presses the manual feeding guide 37. , A biasing member (oblique feed line spring) fixed to the printer, 39 is an upper cover of the printer, 40 is a guide pressure spring for pressing the manual feed upper guide 37 when the upper cover 39 is closed, and 41 is an image forming apparatus. Provided Abutment surface of the hand Sashinobo guide 37,
Reference numerals 42 and 43 denote sheets S conveyed from the manual feed slot 33.
And a transport guide for guiding the sheet S fed from the paper feed tray, and 44 is an exterior.

According to the above construction, the manual feed roller 35, the manual feed oblique feed roller 36, and the manual feed upper guide 37 are the feed roller 12, the oblique feed roller 13, the oblique feed roller holders 14, 32 in the first and second embodiments. Equivalent to manual guide 3
7 has an introduction guide G formed therein.

The conveyance of the manually inserted sheet S is performed as follows. First, the sheet S is inserted from the manual insertion slot 33 by the user's hand, and the leading end S1 of the sheet S is guided by the introduction guide G of the manual upper guide 37 and the transport guide 34, and the manual feed roller 35 and the manual oblique feed roller 36 The tip enters the nip. The skew feed roller 3 uses the skew feed spring 38
Since the sheet S is pressurized, a conveying force and an oblique feeding force are applied to the sheet S, and the sheet S is conveyed while being in contact with the reference plate 29, and is guided by the conveying guides 42 and 43 to advance toward the photosensitive drum. I do.

According to the above configuration, the following effects can be obtained. 1. Since the angle at which the sheet S comes into contact with the skew feeding roller 36 can be reduced (the sheet S comes into contact with the sheet near the horizontal state), the shock applied to the sheet S is reduced, and the manual feed is generally apt to be unstable. It is possible to stabilize the initial state of the paper. 2. When the upper pig 39 is opened for jam removal, the nip pressure between the manual feed obliquely feeding roller 36 and the manual feed roller 35 is reduced, and the processing of the sheet S remaining in the manual feed portion is easy.

FIG. 6 shows a fourth embodiment of the present invention. In the drawing, 1A is a paper feed tray, 45 is a tray transport roller (transport roller) that transports the sheet S picked up by the paper feed roller 3, 46 is opposed to the transport roller 45, and its rotation axis is An oblique feed roller (oblique feed roller) 47, which is taken obliquely with respect to the leading edge S1 and conveys the sheet S while pressing one end of the sheet S against a reference plate (not shown), 47 holds the oblique tray feed roller 46 rotatably. And a leading edge S of the sheet S where a part of the rib enters the oblique tray feeding roller 46.
The tray oblique feed roller holder (oblique feed roller holder) 48 serving as an introduction guide G for guiding the tray 1 presses the tray oblique feed roller holder 47, presses the tray oblique feed roller 46 against the tray transport roller 45, and increases the transport force. A tray skew feeding spring 49 for generating a skew feeding force, 49 is a part of the sheet feeding tray 1A, a tray guide for guiding the sheet S to be picked up, and 50 is a conveyance guide for guiding the sheet traveling direction. 10 to 10 are the same parts as those of the first embodiment. In addition, the tray oblique feed roller holder 47 is provided with the sheet feeding tray 1A.
Is rotatably supported.

According to the above configuration, the feeding of the sheets S from the sheet feeding tray 1A is performed as follows.

The pressing spring 5 is rotated by the rotating paper feed roller 3.
The sheet S on the middle plate 2 pressurized by the movement starts moving by the frictional force. At this time, the multiply fed sheets S are separated by the separation claw 4 so that only one sheet moves. After the sheet S abuts on the tray guide 49, the sheet S is guided by the tray guide 49 and the introduction guide G of the oblique tray feed roller holder 47, and enters the nip portion N of the tray transport roller 45 and the oblique tray feed roller 46. By the pressing force of the skewed tray feeding spring 48, the tray conveying roller 45 and the skewed tray roller 46 apply a conveying force and a skew feeding force to the sheet S, and apply one side edge of the sheet S to a reference plate (not shown). The sheet S is conveyed while abutting S2. Thus, the sheet S is the block guide 1
0 and guided to the conveyance guide 50 and fed to the image forming unit.

In this embodiment, the following effects can be obtained in addition to the effects shown in the first embodiment. 1. In the oblique tray feeding roller 46 which is detachably attached integrally with the sheet feeding tray 1A as in the present embodiment, the hole of the tray guide 49 is enlarged in order to maintain a secure nip. The difference between the positions of the oblique tray feeding rollers 46 must be increased. However, if the introduction guide G is provided on the tray oblique feed roller holder 47, this tray guide 49
The guide guide G of the tray oblique feed roller holder 47 fills the gap between the tray oblique feed roller 46 and the tray oblique feed roller 46, so that the sheet S can be prevented from contacting the tray oblique feed roller 46 at a steep angle, and the occurrence of a jam can be prevented. 2. Since the nip portion N between the oblique tray feeding roller 46 and the tray transport roller 45 can be easily released by attaching and detaching the sheet feeding tray 1A, the jam processing is easy. 3. By providing the tray conveyance roller 45 and the oblique tray feeding roller 46 at the positions shown in this embodiment, a steep angled conveyance path R of the sheet S can be realized, and a space-saving printer can be realized.

[0033]

As described above, the following effects can be obtained by providing the guide for guiding the sheet to the nip portion of the conveying roller and the skew feeding roller by guiding at least two points on the leading edge of the sheet. be able to. 1. Shock when the leading edge of the sheet enters the nip between the transport roller and the skew roller can be significantly reduced,
Realizes stable sheet feeding without jams and skew. 2. Since a pair of a transport roller and a skew roller can be arranged near the confluence of a plurality of transport paths, the degree of freedom of design for exhibiting more reliable sheet feeding performance is increased. 3. Sheet conveyance accuracy is not easily affected by differences in sheet types such as thick paper and thin paper. 4. Since there is no need to consider the accumulation of tolerances on the relative position between the skew feeding roller and the introduction guide, the gap between the introduction guide and the skew feeding roller should be reduced so that the sheet can be smoothly supplied to the nip. Can be.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a printer equipped with a first embodiment.

FIG. 2A is a plan view showing the vicinity of a skew feeding roller of the first embodiment,
(b) is a BB sectional view of (a).

FIG. 3A is a plan view showing the vicinity of an oblique feeding roller according to a second embodiment;
(b) is a CC sectional view of (a).

FIG. 4 is an enlarged longitudinal sectional side view of a main part of a third embodiment.

FIG. 5 is a plan view of a third embodiment.

FIG. 6 is an enlarged longitudinal sectional side view of a main part of a fourth embodiment.

FIG. 7 (a) is a plan view showing a conventional example near a skew feeding roller, and FIG.
FIG.

[Explanation of symbols]

 Reference Signs List 12 transport roller 13 skew roller 14 skew roller holder 15 biasing member (skew spring) 29 side regulating member (reference plate) G introduction guide N nip R transport path S sheet S1 leading edge S2 side edge

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Ando 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Judge Sekiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (72) Inventor Ikuo Ikemori 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References Japanese Utility Model 1-106461 (JP, U) (58) Fields surveyed (58) Int.Cl. ⁶ , DB name) B65H 9/16

Claims (1)

(57) [Claims] 1. A conveying roller and a skew feeding roller which presses against the conveyance roller are arranged in a sheet conveyance path, and the sheet is passed through a nip portion between the conveyance roller and the skew feeding roller. In a sheet feeding device that presses one side edge of a sheet against a side regulating member in the conveyance path to position the sheet left and right, the sheet feeding device includes two ribs that rotatably support the skew feeding roller. An oblique feed roller holder, and an urging member for urging the oblique feed roller holder and pressing the same against the transport holder, protruding into a transport path immediately adjacent to the nip portion so as not to contact the transport roller. A sheet feeding device, wherein an introduction guide for guiding at least two portions of a leading edge of a sheet to the nip portion is formed on the two ribs .